#include<stdio.h>

int sum(int begin,int end)
{
    int ret=0;
    for(int i=begin;i<=end;i++)
    {
        ret+=i;
    }
    return ret;
}

int main()
{
    int begin=1;
    int end=100;
    printf("%d\n",sum(begin,end));
    return 0;
}
